The present disclosure relates to a light emitting device. The disclosure can be applied, for example, to a light emitting device integrated in a fully monolithic style, a manufacturing method thereof, and an optical transceiver.
Along with the progress of the advanced information society, an amount of information transmitted through a network increases at 40 percent per annum. Thus, there is a demand for speeding-up and high functionality of arithmetic operation processors supporting information processors, such as a server and a data center, which process the large-capacity information. One of approaches to capacity enlargement, smaller footprint, and cost reduction asked for the IT equipments is conversion to fiber optics of interconnection. The conversion to fiber optics of the interconnection (optical interconnection) has been more applied to a shorter distance form from inter-chassis to inter-chip via inter-board and intra-chip.
A transmitter and a receiver of the optical interconnection each include optical components such as a light source, a modulator, and a receiver. A silicon photonics technology that integrates these optical components by using a silicon CMOS process technology has been activity researched in recent years. The silicon photonics is a technology which uses silicon as a material of the photonic device, and for which the highly-developed silicon CMOS process technology can be used, hence enabling the micro-fabrication and the mass batch production. The silicon photonics using the silicon CMOS process technology is a low-cost optical integrated circuit manufacturing technology.
The light source has a first, second, and third method: the first method, as shown in a non-patent document 1 of Adithyaram Narasimha et al.: “A Fully Integrated 4×10 Gb/s DWDM Optoelectronic Transceiver in a standard 0.13 μm CMOS SOI”, International Solid-State Circuits conference 2007 pp. 42 to 43,586, describes a method to introduce light emitted from a Continuous Wave (CW) laser from the outside to a silicon photonics integrated chip. The second method, as shown in a non-patent document 2 of Yutaka Urino et al.: “First Demonstration of High Density Optical Interconnects Integrated with Laser, Optical Modulators and Photodetectors on a Single Silicon Substrate”, European Conference and Exhibition on Optical Communication 2011 We9LeSaleve4”, describes a method to realize a light source by mounting a semiconductor laser chip onto a silicon photonics chip. The third method, as shown in a non-patent document 3 of Matthew N. Sysak et al.: “Reduction of hybrid silicon laser thermal impedance using Poly Si thermal shunts”, Optical Fiber Communication Conference and Exhibition 2011 OWZ6, describes a method to form an active layer made of a compound semiconductor on a silicon photonics integrated chip by bonding. With regard to germanium as a material system having an affinity with the silicon CMOS process, as shown in a non-patent document 4 of Rodolfo E. Camacho-Aguilera et al.: “An electrically pumped germanium laser”, Optics Express, 2012, Vol. 20, No. 10, pp. 11316-11320, there is reported a laser using a Fabry-Perot resonator with its end face cleaved.
In general, since a silicon waveguide and a semiconductor laser that configure an optical integrated circuit are different in optical mode distribution from each other, mode matching based on mode conversion is required. A mode conversion system in the semiconductor laser is disclosed in JP-H08-116135-A (Patent Document 1), JP-H10-098231-A (Patent Document 2), JP-2005-210120-A (Patent Document 3), and JP-H10-117045-A (Patent Document 4).